Idaho and National Immunization Rates

The Idaho Immunization Program (IIP) and the U.S. Public Health Service are committed to reaching the Healthy People 2020 objectives for vaccinations. To measure national progress toward this goal, the Centers for Disease Control and Prevention (CDC) conducts the National Immunization Surveys (NISs) including the Child NIS and the Teen NIS. State immunization programs use the state-level data to track the progress they are making in improving immunization rates for those vaccines where the Healthy People 2020 targets have not yet been reached, and to inform program activities. NIS data are collected by interviewing households in all 50 States, the District of Columbia, and selected areas for oversampling. The NIS is a list-assisted random-digit-dialing telephone survey, followed by a mailed survey to children’s immunization providers.

The NIS is conducted for the CDC by the National Opinion Research Center (NORC) at the University of Chicago. If you have any questions about the National Immunization Survey, please visit the NIS website or call the NORC toll free at 1-866-999-3340.
Overview of the Child NIS

The target population for the Child NIS is children aged 19 through 35 months living in the United States at the time of the interview. Data from the Child NIS are used to produce timely estimates of vaccination coverage rates for all childhood vaccinations recommended by the Advisory Committee on Immunization Practices (ACIP). The official estimates of vaccination coverage rates from the Child NIS are rates of being up-to-date with respect to the ACIP-recommended numbers of doses of vaccines. Vaccinations included in the survey are: diphtheria and tetanus toxoids and acellular pertussis vaccine; poliovirus vaccine; measles, mumps, and rubella vaccine; Haemophilus influenzaetype b vaccine; hepatitis B vaccine; varicella zoster vaccine; pneumococcal conjugate vaccine; and hepatitis A vaccine.

Child NIS data are released in late summer of the year after they are collected. For example, the NIS that is conducted in 2013 was released in 2014. Here is a diagram showing the timeline from the birth of each child in the NIS sample, to the date the data are released.
Overview of the Teen NIS

The target population for the Teen NIS is teens aged 13 through 18 years living in the United States at the time of the interview. Data from the Teen NIS are used to produce timely estimates of vaccination coverage rates for all childhood vaccinations recommended by the Advisory Committee on Immunization Practices (ACIP). The official estimates of vaccination coverage rates from the Teen NIS are rates of being up-to-date with respect to the ACIP-recommended numbers of doses of vaccines. Vaccinations included in the survey are: diphtheria and tetanus toxoids and acellular pertussis vaccine; poliovirus vaccine; measles, mumps, and rubella vaccine; Haemophilus influenzae type b vaccine; hepatitis B vaccine; varicella zoster vaccine; pneumococcal conjugate vaccine; and hepatitis A vaccine.

Teen NIS data are released in late summer of the year after they are collected. For example, the Teen NIS that is conducted in 2013 was released in 2014. Here is a diagram showing the timeline from the birth of each child in the NIS sample, to the date the data are released.

Comparing the Childhood Vaccine Series

In addition to individual vaccines, the Child NIS also estimates the immunization rates for several vaccine series. These series are represented by a string of numbers separated by colons, for example 4:3:1:3:3:1:4. The percentage associated with this vaccine series indicates the estimate of children who have received at least 4 doses of the diphtheria, tetanus and acellular pertussis vaccine, 3 doses of polio vaccine, 1 dose of measles, mumps and rubella vaccine, 3 doses of Haemophilus influenzae type b vaccine, 3 doses of hepatitis B vaccine, 1 dose of varicella vaccine, and 4 doses of pneumococcal conjugate vaccine.

As new vaccines are added to the recommended vaccination schedule, the “gold standard” vaccine series (the one that is used to establish what “up to date” means currently) changes. The old vaccine series continue to be measured for several years to give states the ability to compare older data with newer, which is why shorter vaccine series such as the 4:3:1:3:3:1 series (which does not include the 4 doses of pneumococcal conjugate vaccine) is still reported on the NIS.

The explanation for what vaccines are included in each series is in the footnotes of each of the graphs linked on this page.

National Immunization Survey Confidence Intervals

In statistics, a confidence interval (CI) is a measure of the reliability of a point estimate. In the NIS graphs linked on this page, the CI is indicated by the vertical bars above and below each point estimate. The smaller a sample size compared to the population that is being surveyed, the wider the confidence interval. The NIS is designed to determine accurate national immunization rates, but the data are also released at the state level. The Child NIS estimates of immunization rates of all children in Idaho who are aged 19 through 35 months of age (more than 40,000 total children), are based on surveying fewer than 300 children. The Teen NIS estimates of immunization rates of all children in Idaho who are aged 13 through 17 years of age (over 100,000 total children), are based on surveying fewer than 400 children.